The objective of the proposed study is to delineate the regulatory events governing immune responses in ocular compartments associated with the mucosal immune system. The specific aims are: 1. to develop methodology capable of optimizing antibody responses in tears and to employ these methods to study events governing the expression of specific antibody populations, 2. to characterize immunocompetent cells and to detail cellular traffic patterns associated with the lacrimal and conjunctival compartments of the eye, 3. to study the fate of antigen following mucosal application and 4. to assess transport of serum immunoglobulins into tears and ocular structures. The rat model will be employed to assess the effects of antigen dosage, mucosal adjuvants and combinations of topical and gastrointestinal immunization routes on the patterns of antibody expression in tears, other secretions and serum. Antibody spectrotype (isoelectric focusing) and idiotype distribution (anti-idiotypic reagents prepared against monoclonal antibodies derived from somatic cell hybridization) will be used to probe the expression of specific antibody populations. The characterization of immunocompetent cells in lacrimal glands and conjunctival tissue will be carried out using both immunohistochemical and cell isolation (lacrimal gland only) methodology. Cell traffic patterns responsible for the distribution of antibody producing cells will be detailed using immunohistochemical methods. The adoptive transfer system will be employed to study cell migration between distal mucosal sites and into ocular compartments. The lymphocyte-high endothelial venule binding assay will be developed and applied to the rat system in order to approach fundamental questions relating to control of the homing process. Combinations of immunohistochemical (immunofluorescence and autoradiography) and radioimmunoassay procedures will be employed to assess antigen localization following mucosal application and the transport of immunoglobulins (including hybridoma antibodies) into tears and ocular structures. The results of these studies will provide a more complete understanding of the immunobiology of the eye and have direct application to the design of effective vaccination procedures for relevant ocular pathogens.